Photographer Paul Nicklen, who has been with National Geographic for 17 years, says recording the video was even more heartbreaking. He’s spent his life filming bears and estimates that he’s come across about 3,000 of them, but the animal in his latest video was unlike the rest. In an article about the clip, Nicklen recalled, “We stood there crying — filming with tears rolling down our cheeks.”

Nicklen says he’s often asked why he didn’t do something, but he explains, “Of course, that crossed my mind. But it’s not like I walk around with a tranquilizer gun or 400 pounds of seal meat.” He added, “When scientists say bears are going extinct, I want people to realize what it looks like. Bears are going to starve to death. This is what a starving bear looks like.”

Unfortunately, animals seem to have a very bleak future in front of them. The No. 1 threat to the world’s 22,000 polar bears is climate change, according to a World Wildlife Foundation report. The bears spend the winter months on the ice, where they do a lot of laying around and a whole lot of eating seals; they fast during the summer. But as the winter months have become warmer, it takes longer for the ice to reappear each season, meaning that the animals have less time to eat, and they have to fast for a longer stretch of time. In short, no ice means no seals, which could soon mean no polar bears.